I’m a huge fan of these folks! If you have the time I definitely recommend having a listen.

Last week I saw a motor cycle crash patient. Nothing urgent or too fancy, just a simple accident to start a night in the ED on my first shift of an emergency ultrasound elective. I thought I’d get to practice my FAST exam, maybe sew up a few lacs, or so I thought….

As I sit down to interview the patient, I smell alcohol (Great. That explains the cop standing next to the door). An impaired patient interview and physical exam is not the uncomplicated lac repair/ultrasound practice I was looking for, but I’m already here so might as well get some practice. I ask about the accident; 30-35 mph, single vehicle accident, no impact (other than the ground). So far so good. He has a cut on his head, so I ask about his helmet. No helmet. Really? My uncomplicated case just got more complicated. I continue. Just a little head pain (2/10). Not terrible. He’s not sure about loss of consciousness, “I don’t think so, but maybe.” Ugh. Not helpful. He has back pain too. Not good either. I round my way to medical history and things get complicated again. Of course he has a mechanical heart valve. And is taking Coumadin. Why not? My simple ultrasound practice case is no more.

I do a physical exam. No obvious head abnormalities, other than a small cut on his forehead. He’s positive for tenderness over his thoracic and lumbar spine. Neuro exam is normal (for a drunk guy). Physical exam done. I pull my thoughts together and present the case to the attending. I take a deep breath and start, “45 year old male presents with… ” I finish and mentally pat myself on the back. Success! As a new-to-seeing-patients med student, small successes like a good patient presentation make me do a little happy dance. He says, “Okay. What would you do next?” Oh crap. I know he needs blood tests (especially an IRN & PT given his Coumadin) and definitely X-Rays given the spinal tenderness, but does he need a head CT? He’s borderline to me. 2/10 head pain, normal neuro exam, and he was only going about 30 mph. On the other hand, he wasn’t wearing a helmet, he’s a little drunk (not a lot), and taking Coumadin. Does he need a head CT?

The Canadian CT Head Rule & New Orleans Criteria to the Rescue!

For minor head injury patients (GCS 13-15) apply the CCHR or NOC decision making tools to help you decide if a head CT is required.

Canadian CT Head Rule:

Head CT is only required in minor head injury patients with any one of the following:

Mild traumatic brain injuries are common, but the consequences of missing a serious brain injury can be life threatening. Why is that? Well I’m glad you asked. The brain is housed in an inelastic container (the skull) that has limited room for expansion. In the event of a brain injury, swelling or bleeding can cause a rapid increase in intracranial pressure. Increased intracranial pressure leads to extreme cases of badness and can result in long-term neurological damage or death. With so little room to expand brain badness can happen fast!

Ok. So a positive CT exam is bad, but these are minor head injury patients. How often does that really happen? In the Canadian CT Head Rule study, 8% of minor head injury patients had clinically significant brain injuries and 1% required neurological intervention. That means that 2 out of 25 mild head injuries will have clinically significant brain injuries AND 1 in 100 are going to need neurological interventions. That’s a quite a few patients.

Common causes of traumatic brain injuries include motor vehicle collisions, falls, assaults, sports-related injury, and penetrating trauma. So keep an eye out for minor head injuries if you seen these.

Let’s think back to our patient. GSC of 15, normal neuro exam, head pain is 2/10, unlikely but possible LOC. Intoxicated but not too badly. He crashed his motor cycle going 30ish mph, but had no helmet. Physical exam showed a small head laceration. Does he need a head CT?

The Canadian Guidelines:

– Doesn’t apply because of Coumadin use… get a head CT!

– Let’s pretend there’s no Coumadin involved. What risk factors does he have?

– Dangerous mechanism, maybe. A motor cycle crash with no helmet sounds significant to me. It’s not specified on the CCHR dangerous mechanism list, but I think a helmetless motor cycle crash would probably count. Let’s get that man a CT!

The New Orleans Guidelines:

– What risk factors do we see now?

– Headache (a minor one), evidence of trauma above the clavicles, and alcohol intoxication. He definitely qualifies for a CT!

After looking at both guidelines, I would definitely order a head CT for this case. The patient received a head CT under the Canadian guidelines because of his hypo-coagulative state (Coumadin). If there wasn’t Coumadin involved, he still would have gotten a CT for his dangerous mechanism of injury. The patient received a head CT under the New Orleans guidelines because he had a headache, evidence of trauma above the clavicles, and was intoxicated. Both guidelines are excellent decision making tools that add helpful information when deciding if a minor head injury patient needs a head CT. While neither guideline should serve as a substitute for clinical judgment, both provide valuable evidence-based information to enhance the decision process in evaluating the need for CT scans in minor head injury patients.